Drilling machine



May 6, 1958 F. H. MUELLER DRILLING MACHINE Filed DBO. 13, 1955 8Sheets-Sheet 1 May 6, 1958 F. H. MUE-LL'ER DRILLING MACHINE 8Sheets-Sheet 2 Filed Dec. 13. 1955 I UQFEED all T INVENTOR FRA/VK H.MUELLE? ATTORNEYS May 6, 1958 A F. H. MUELLER 2,833,167

DRILLING MACHINE v Filed Deo. 13, 1955 8 sheets-sheet s INVENTOR FRANKh'. MUELLER ATTORNEYS F. H. MUELLER 2,833,167

DRILLING MACHINE 8 Sheets-Sheet 4 m a U M H. i@ .Bv @Q m NN wg f NQ vh.W- vm. om. KS mm2., v o. om. E EEU May 6, 1958 Filed Deo. 1s, 1955 May6, 1958 F. H. MU ELLER DRILLING MACHINE 8 Sheets-Sheet 5 Filed Dec. 13,1955 May 6, 1958 F. H. MuELLl-:R 2,833,167

DRILLING MACHINE Filed nee. 15, 1955 s sheets-sheet e INVENTOR FRA/Vl(H. MUELLER ATTORNEYS 1 May 6, 1958 F. H. MUELLER DRILLING MACHINE 8Sheets-Sheet 7 Filed D60. 13, 1955 INVENTOR FRA lvl( H. Mug/ L ERATTORNEYS May 6, 1958 F. H. MUELLER 2,833,167

DRILLING MACHINE Filed Dec. 13, 1955 8 Sheets-Sheet 8 INVENTOR FRA/VKh'. MUELLE? nnrLLnvG MACHINE Frank H. Mueller, Decatur, Ill., assignorto Mueller Co., Decatur, Ill., a corporation of Illinois ApplicationDecember 13, 1955, Serial No. 552,886

26 Claims. (Cl. 77-42) This invention relates to machines for drillingor tapping mains and pipes without escape of fluid pressure therefrom,and more particularly pertains to improvements in drilling machines ofthe type disclosed in U. S.

Patents Nos. 1,956,129, 2,470,044, and 2,646,699. p

Drilling machines of the type disclosed in the foregoing patents areprovided with a pressure-tight housing completely enclosing a boring barthat usually is driven by power but can be rotated by hand. The machineshave lfeed mechanism for advancing the boring bar, and the tool carriedthereby, and are also equipped with an automatic drive for the feedmechanism to advance the bar at a rate appropriate for a cuttingoperation. The automatic drive includes a clutch device which, upon itsdisengagement, permits hand advance of the boring bar by the rotation ofa crank handle connected to the feed mechanism. Advance of the boringbar by hand usually is at a much faster rate than that effected by theautomatic drive in order to obtain rapid advance of the cutting toolfrom a fully retracted position into engagement with the work, and rapidretraction from the work on completion of a cutting operation.

Since the boring bar of drilling machines of the type underconsideration is completely enclosed, there arises the problem ofdetermining the axial position of the boring bar at all times. 'Machinesof the foregoing type are employed in many instances for drilling ortapping operations on mains and pipes that are under high pressure, andin such an operation it will be seen that the feed mechanism and theautomatic drive therefor will remain under a heavy load after a hole hasbeen cut into the pipe, because further advance of the boring bar isresisted by the high fluid pressure in the main or pipe. Thus, there isno obvious indication to an operator of the machine that the drilling ortapping operation has been completed. ln some instances, thisdisadvantage, particularly when operating on a pipe of relatively smalldiameter, has resulted in the operator neglecting to shut off the powerto the machine so that the boring bar continues to advance and cuts ahole in the opposite side of the main. Unless such a dual cut isintended and the appropriate apparatus provided therefor, the second cutcould have disastrous effects.

lt thus will be seen that it would be highly advantageous to providemeans in a machine of the type under consideration for continuouslyindicating the extent of advance of the boring bar from a fullyretracted position. lt is, therefore, an object of this invention toprovide such a universal travel indicator that is relatively simple,accurate in operation, involves no change-speed mechanism forcompensating for the differences between automatic and hand rates ofadvance, and requires no adjusti mensions.

2,833,167 Patented May 6, 1958 preset feed mechanism with means forindicating the predetermined extent of advance of the boring bar setinto such feed mechanism, and to so construct the indicator and thepresent feed mechanism that the indicator will be returned to a zeroindication after the boring bar has advanced through'the predetermineddistance.

When a machine of the type under consideration is equipped with alpreset. feedy mechanism operating to disengage a clutch device in theautomatic drive for the feed mechanism, it will be seen, as pointed outabove, that in many instances the feed mechanism and its automatic drivewill be' under a considerable load at the time that the clutch device isdisengaged. Disengagement of a clutch device while under load presentsno problem when such device is of the friction type. Drilling machinesof the type under consideration, however, require the transmission ofconsiderable power through the automatic drive in order to advance theboring bar, even after a hole has been cut in a high pressure main.Obviously, it is highly desirable to keep the housing enclosing theautomatic drive within reasonable size limits, but a friction typeclutch capable of transmitting the necessary power through the automaticdrive must, of necessity, be so large that it cannot be housed within adrilling machine housing of reasonable and practical di- Consequently, apositively-engageable clutch device must be used to transmit the powerthrough the automatic drive.

Disengagement of a positively-engageable clutch device under load,however, gives rise to an immediate difticulty. It will be seen that ifa positively-engageable clutch device (which includes such mechanisms asslidably-disengageable meshing gears, the two parts of a dental or jawclutch, a dive key disengageable from a slot or groove in another part,and the like) is disengaged under load, metal will be chipped or shavedfrom the disengaging parts at the moment of disengagement. Theconsequent result will be that the positively-engageable clutch devicewill be damaged practically beyond repair after only a fewdisengagements while under load. Furthermore, it requires excessiveforce to disengage a positively-engageable clutch device under load.

Consequently, it is also an object of this invention to provide amechanism for automatically relieving the load on a power train, whichincludes a positively-engageable clutch device, during the disengagement,-f such device to thereby permit disengagement of clutch device withoutany load thereon, and, consequently, with no damage thereto. lt isanother object to so interconnect the load-relieving mechanism and theclutch device that the load is relieved prior to any disengagingmovement of the device so that the force necessary to effectdisengagement is minimized.

Other objects and advantages of the invention will become apparent fromthe following description and accompanying drawings in which:

Figure l is a side View, partially in longitudinal section, of adrilling machine embodying this invention;

Figure 2 is an end view of the machine shown in Figure l and taken fromthe right-hand end of the latter figure; i

Figure 3 is an enlarged, fragmentary view of the right-hand portion ofFigure 1;

Figure 4 is an enlarged,"'fragmentary, sectional View takensubstantially on lines4-4 of Figure 2;

Figure 5 is an enlarged;d fragmentary, sectional view takensubstantially onlines S-,5 of Figure 2;

Figure 6 is -an enlarged, fragmentary side view taken substantially onlines 6-6 of Figure 1, but with parts of the housings being broken awayto illustrate details;

Figure 7 is an enlarged, sectional view taken substantially on lines 7-7of Figure 1;

Figure 8A is a reduced sectional View taken substantially on lines S-8of Figure 3;

Figure 9 is'a reduced sectional view taken on lines 9-'9 of Figure 3;

Figure 10 is a sectional view taken substantially on lines 10-10 ofFigure 3;

Figure `11 is a fragmentary; sectional view taken substantially on lines11-p-11 of Figure 3;

Figure 12 is a fragmentary, sectional view taken substantially on lines12-12 of Figure 6;

Figure 13 is an enlarged sectional view taken substantially on lines13-13 of Figure 6;

Figure 14 is an enlarged, fragmentary, View, with parts being omittedfor purposes of clarity, taken substantially on lines 14-14 of Figure 3;

Figure 15 is a view corresponding to Figure `14 but illustrating adifferent position of the parts;

Figure 16 is a fragmentary, sectional view taken on lines 16-16 ofFigure 14;

Figure 17 is a perspective view of the key shown in Figures 14 and 15;

Figure 18 `is an enlarged, fragmentary view of a portion of Figure 3;

Figure 19 is an enlarged, fragmentary sectional view taken substantiallyon lines 19--19 of Figure 18;

Figure 20 is an enlarged, fragmentary view of a portion of the left-handside of Figure 1.

Referring now to Figures 1 and 3 of the drawings, there is shown adrilling machine embodying this invention having a barrel provided witha `bottom ange 32 forming the top wall of a lower gear housing 34. The

housing 34 has a removable lower wall 36 having a tubular bearing andguiding extension 38, which is aligned with the barrel 30 and providedwith a circumferential ange at its extremity for bolting the machinerinthe usual manner to one end of a valve (not shown). At its upper end,the barrel is provided with a plate-like eccentric circumferential ange42 which, `in conjunction with an inverted bowl-like top cap 44 boltedthereto, constitutes an upper gear housing 46 having a lifting handle48.

Journaled in bushings 50 and 52 in the upper and lower ends,respectively, of the barrel 30 is a drive tube 54, the upper and lowerends of which project, respectively, into the upper and lower housings46 and 34. A pair of gears S6 and 58 is secured `by a key 60 (Figures 3and 10) to the upper end of the tube S4 within the housing 46. Fixed, asby a key 62, to the lower end` of the drive tube 54 and having its hubbearing against a thrust washer 64 interposed between the lower end ofthe drive tube and the lower wall 36 of the lower housing 34, is abeveled gear 66 engaged by a pinion gear 68 fixed to a driving stubshaft 70 journaled in a bearing 72 fixed in a side Wall of the housing34. The stub shaft 70 may be suitably driven by an appropriate motor(not shown).

Received in the drive tube 54 is a hollow `boring bar 74, the upperportion of which has a close sliding t in the drive tube and is splinedthereto for rotation thereby and axial movement relative thereto by apair of keys 76 secured to the bar and slidable in diametricallyopposite 'interior longitudinal grooves or keyways'77 (Figures 9 and`111) :extending thelength of the drive tube 54. Be-

neath its upper portion the boring bar 74, for the .purpose Q4, ofreducing friction, is externally reduced so that a downwardly facingshoulder 78 (Figures 3 and 4) exists. The lower reduced portion of theboring bar 74 is journaled in a sleeve bearing 80 in the tubularextension 38 of the lower housing 34. The extension 38 preferably isprovided with an upper oil seal in the form of an O-ring 82 and alsowith a lower appropriate pressure seal in the form of a stuing box 84.The lower end of the boring bar 74 is closed and provided with a socket36 for the reception of a tool (not shown). The upper interior portic-uthe boring bar 74 is enlarged to provide a shoulder 33 (Figures 3 and 4)which supports an inwardly overhanging abutment ring against which isseated a coaxial feed nut 92. The nut 92 is fixed against rotationrelative f' to the bar 74 by keys 94 and fixed against axial movementrelative to the bar by a retaining ring 96 threaded into the upper endof the boring bar and locked in place -by set screws 98 (Figure 3)bearing against the upper end of the nut 92.

A hollow feed screw 100 is engaged within the nut 92 and dependscoaxially within the boring bar `74. The upper end of the screw 100 hasan enlarged, Unthreaded extension 102 which extends through the uppergear housing 46 and projects through, and is journaled in a sleevebearing 104 supported by, the top cap 44. The projecting outer end ofthe screw extension 102 has a retaining washer 106 pinned thereto andbearing against a thrust washer 108 mounted against the outer side ofthe cap 44. Outwardly beyond the retaining washer 106, the screwextension 102 terminates in a squared or otherwise noncircularly formedouter end 110 for reception in the complementary socket 112 of a crankhandle 114. Within the gear housing 46 the screw extension 102 has agear 116 keyed thereto with the gear hub engaging an anti-frictionthrust bearing 118 interposed between the gear 116 and a thrust collar120 xed to the upper wall of the cap 44. It thus will be seen that thefeed screw 100 is fixed against axial displacement by the gear 116 andthe retaining washer 106.

The feed nut 92 and the feed screw 100 constitute the feed mechanism ofthe machine for advancing the boring bar 74 on relative rotation betweenthe nut and screw. In a machine of the type under considerationdesigned, for example, to make a cut 6 inches in diameter into a main,the length of the barrel 30, the boring vbar 74, and the feed screw 100may be such as to permit the boring bar to have an overall travel, i.e., from its fully retracted position shown in Figures l, 3, and 4 ofthe drawings to a fully extended position, of about 24 inches. In such amachine the pitch of the feed screw threads is usually such that onecomplete revolution of the screw 100 rela tive to the feed nut 92 movesthe boring bar 74 axially one-tenth of an inch.

An `axtally-shiftable countershaft 122 is journaled in a cap bearing 124mounted in the flange 42 constituting the lower wall vof the upperhousing 46 and in a sleeve bearing 126 mounted in the cap 44, inlaterally spaced, parallel relation to the feed screw 100. The upper endof the countershaft 122 projects out of the housing 46 and has anoperating knob 128 pinned thereto. Stacked on the countershaft v122 inthe following order and held against axial movement between the capbearing 124 and the sleeve bearing 126 are: a spacer washer 130, aspacer washer 131 having a pair of gears 132 and 134 rotatably journaledthereon'and pinned together for rotation as a unit, a gear 136selectively connectable and disconnectable with the countershaft 122 forrotation therewith or relative thereto, the bearing portion or hub 138of a rocker arm 140, a spacer washer 142, a gear 144 keyed to thecountershaft 122 for rotation therewith by special means laterdescribed, and a cam sleeve 146 journaled on the countershaft 122.

The gear 144 is in constant meshing engagement with the gear 116 on thefeed screw 100 while the gear 136 is in constant ineshing engagementwith the gear 56 on the drive tube 54. Consequently, when the gear 136rotates with the countershaft 122, the gears 56 'and 136, thecountershaft 122, and the gears 144 and 116 form a power train thatconstitutes an automatic drive for the feed mechanism. The ratios of thegears 56, 136, 144, and 116 in the automatic drive are such that, whenthe gear 136 is fixed against rotation to the countershaft 122,'rotation of the drive tube 54 drives the feed screw 100 at a slightlygreater rate of rotation than the feed nut 92 to advance the boring bar74 at an appropriate rate for cutting a main. Thus, for example, thegearing ratios for the automatic drive may be such as to cause theboring bar 74 to advance one-tenth of an inch on 20 revolutions thereof.

The automatic drive is rendered operative or inoperative by connectingor disconnecting the gear 136 to or from the countershaft 122 by ap-ositively-engageable clutch mechanism. For this purpose thecountershaft 122 has a longitudinally-extending slot 148 (Figures 3 andll) in which is secured,V as by a transverse pin 150, the base or footportion of a Ispring key 152, normally termed a dive key, which isreceived with sliding clearance in the slot. The head of the key 152 isurged by its spring shank to project out of the slot 148 for engagementwithin a longitudinal groove 154 in the interior of the hub of the gear136. The key 152 is engaged and disengaged with the gear 136 by axialmovement of the countershaft 122 which may be shifted manually by theknob 128. Thus, when the countershaft 122 is in the axial position shownin Figure 3, the key 152 projects into the groove 154 in the gear 136 soas to tix the latter against rotation to the countershaft, but when thelatter is shifted to the left, an angular face 156 on the key, whichbears against the edge of the aperture in the washer 131, cams the keyhead back into the slot 148 and out of engagement with the gear 136.

In this latter de-clutched or hand feed position, manual rotation of thefeed screw 100, by the crank handle 114, when the drive tube 54 and,consequently, the nut 92 are at rest, rotates the -feed screw at a ratefast enough to rather rapidly thread the nut 92 therealong for a fastadvance or retraction of the boring bar 74. The knob 128 also may beprovided with a lsquared end 158 for the reception of the crank handle114 so that the latter may be applied either to the countershaft 122 orthe feed screw extension 102 for manual feed. For the purpose ofyieldably retaining the countershaft 122 in either of its two axialpositions, it is provided with spaced, circumferential grooves 160 and162 for the reception of a spring-pressed ball detent 164 mounted in thecam sleeve 146.

A universal boring bar travel indicator embodying this inventionincludes a conventional rotatable counter 166 (Figures 4, 6, and 7), setto register zero in the fully retracted position of the boring bar 74and designed to register the extent of advance of the latter from suchposition in inches and tenths of an inch. The counter 166 is mounted in'a housing 168 secured, as by welding, to the barrel and the undersideof the flange 42 constituting the bottom of the housing 46 and isprotected from damage or abuse by a detachable cover 170 having a clearplastic window 172 (Fig. 7) therein registering with the face of thecounter. The counter 166 is `driven by a differential gearingarrangement, best shown in Figures 4, 6, land 10, which drives thecounter at the differential rate of rotation between the feed nut 92 andthe feed screw 100.

For this purpose, a counter drive shaft 174, disposed in spaced parallelrelation to the countershaft 122 and the feed screw 100, has one endthereof journaled in a cap bearing 176 mounted in the gear housing cap44 and the other end thereof journaled in and projecting out of atubular bearing 178 mounted in the flange 42. The outer end of the shaft174 is pinned to the stem 180 of thev 6 counter 166. A carrier 182for aring gear 184 has'a gear 186 fixedV thereto and is journaled forrotation ona tubular extension of a planetary gear carrier 188 which iscoaxially mounted on and pinned to the shaft 174. Afsun gear19t1concentn'c with the ring gear 184 is carriedby a sleeve extension ofanother gear 192 which is journaled for rotation on Va bushing 194mounted on the shaft 174; nter-posed between the sun gear 190 and thering gear 184 and meshing with both are a plurality of planetary gears196 carried by the planetary gear carrier 188. Thegear i 1.86 constantlymeshes with the gear 58 on the drive tube 54, while the gear 192constantly meshes with the gear 144 on the countershaft 122. The ratiosbetween the gears 5S and 186, and the gears 144 and 192 are proportionedso that the respective rates of rotation of the ring gear and sun gear190 are directly proportional to the rates of rotation of the feed nut92 and feed screw 100.` Consequently, the planetary gear carrier 188land the shaft 174 rotate at a rate proportional to the differentialrate of rotation between the feed nut 92 and the feed screw 100.

Thus, it will be seen that when the boring bar 74 is advanced by eitherautomatic or manual feed, the counter 166 will be driven at a ratedirectly proportional to such differential rate. The counter 166 isinternally geared or constructed to register the number of revolutionsof the shaft 174 in terms of inches and tenths of an inch of boring baradvance.

The machine also embodies a preset feed mechanism which` can be adjustedso that when the machine is in automatic feed and the boring bar 74advances a predetermined distance from any axial position of such bar,the automatic drive will be disengaged and stop further advance of theboring bar. For this purpose the preset feed mechanism includes meansfor shifting the countershaft 122 from its automatic feed to its handfeed position. This shifting means includes the cam. sleeve 146 which isjournaled on the countershaft 122 and has one end thereofcounterbored toform a shoulder 198 (Figures 3, 5, 18, and 19) provided withdiametrically opposite, V-shaped cam grooves 200 within which ride theopposite endsl of a pin 202 extending diametrically.

through the shaft 122 when the latter is in its automatic feed position.,'When the cam sleeve 146 is free to rotate, the camming action betweenthe projecting ends of the pin 202 and the sides of the c am grooves 200will be ineffective to exert axial forces between the vcam sleeve andthe countershaft 122. If the cam sleeve 146 is restrained againstrotation, however, it will be seen that the projecting ends of the campin 202 will ride up the side walls of the cam grooves 200 and force thecountershaft 122 .to shift to the left from its automatic feed to itshand feed position. In suchlatter position of the countershaft 122, theprojecting ends of the cam pin 202. clear the shoulder 198 in the camsleeve 146 so that the countershaft can rotate freely relative to thecam sleeve and enable` operation of the manual feed. f

The apparatus for arresting rotation of the cam sleeve 146 constitutesthesettable part of the preset feed mechanism, and includes anaxially-shiftable adjustable shaft 204 (Figures 5 and 6) disposed inparallel, spaced relation to the 'feed screw 100, the countershaft 122,and the shaft 174. The opposite ends of the shaft 204 are journaled inand project through tubular bearings 206 secured in the cap 44 andflange 42 of the gear housing 46. A gear 208 is pinned on the shaft 204and can be moved into or out of mesh with the gear V132 journaled on thecountershaft 122 by axial shiftingof the yshaftV 204. As is shown in thedrawings, movement of the shaft 204 to the left, as by a knurledadjustment knob 210 secured on its projecting end, moves the gear 208out yof mesh with the gear 132. The gear 134, which is pinned to thegear 132, is driven by a gear 212 pinned to-the counter drive shaft 174,as shown in Figure 13.

Thus, rthe shaft204 maybe rotated by the shaft 174, at

7 a rate proportional to the rate of advance of the boring bar` 74.Because of space limitations, later described more in detail, it isdesirable for the shaft 204 to rotate at arate considerably'less thanthat of the shaft 174. For such a reduction drive, the gear 212 has buta single tooth thereon, while the gear 134 hasten teeth thereon. TheAconstruction of these gears 134 and 212 is such that the shaft 204rotates through one-tenth of a rotation for every revolution of theshaft 174.

A preset travel indicator, in the form of a rotatable counter 214similar to the counter 166, is also mounted in the housing 168 and theprotective cover 170 is provided with `a second clear plastic window 216(Figure 7) registering with the face of the counter 214. The stem of theAcounter 214 is connected to the other projecting end of the shaft 204by a connection which permits relative axial movement between the stemand the shaft, as by a slot 220 inone end of the shaft 204 engagingatransverse pin 222 within a tubularmember or sleeve` 224 fastened tothe stem 218 of the counter 214. The counter 214 is constructed toregister the revolutions of the shaft 204 in terms of inches .and tenthsof an inch of advance of the boring bar 74 through a preset feeddistance. f

Intermediate its length, the shaft 204 is threaded and has an elongated,automatic feed nut 226 engaged therewith. Enclosing the nut `226 is anautomatic feed tube 228 which is restrained against rotation but fixedto the shaft 204 ,for axial movement therewith, as by means of aninturned circumferential flange 230 on the tube interposed between thehub of the gear 208 and a thrust washer 232 bearing against a thrustcollar 234 fixed on or integralwith the shaft 204. The tube 228 has alongitudinal slot 236 throughout a portion of its length for thereception 'of a radial lug 2,38 on the nut 226 to restrain rotation ofthe latter on rotation of the shaft 204. Consequently, rotation of theshaft 204 moves thek Y nut 226 axially therealong. Fixed on theautomatic feed tube 228 is a radial arm 240 (Figures 5, 6, 12, and 19)which serves the dual functions of restraining the tube 228 againstrotation and also arresting rotation of the cam sleeve 146 when theshaft 204 is shifted to the left to disengage the gears 208 and 132. Forthis purpose the yarm 240 has an aperture thereinrotatably receiving aportion of the cam sleeve 146. A counterbore 242 .at one end of theaperture is provided with a radial lug 244 (Figure 19) engageablewith aradial lug 246 on and adjacent one end ofthe cam sleeve 146, when thearm 240 is shifted to the left Vwiththe automatic feed tube 228, toarrest or prevent rotation of the cam sleeve.` As previously described,such arrestment will automatically shift the countershaft 122 fromautomatic to hand feed position.

The` automatic feed tube 228, `and consequently the l adjustable shaft204, are constantly urged to shift to the left, into the axial positionwherein the gears 208 and 132 are disengaged andthe lugs 244 and 246 areengaged, by a spring 248 surrounding the feed tube and interposedbetween the arm 240 andthe top cap 44 of the gear housing 46. In orderto retain theshaft 204 in its righthand gear-engaging andlug-disengaging position against the action of the spring 248, there `isprovided a detent or trigger mechanism in the form of a beveled shoulder250 (Figure 5) on the tube 228 engaging a complementary shoulder 252 inan oversized aperture in the rocker arm 140 receiving the automatic feedtube. The rocker arm 140 is urged into a position to retain the beveledshoulders 250 and 252 in engagement against the `action of the spring248by a plunger 254 (Figures 8 and 10) slidable in a bore in the rocker armextending radially of the aperture and urged against a side of theautomatic feed tube 228 by a spring 256. The friction thus developedbetween the interengaged shoulders 250 andl252 normally, is sufficientto retain the shaft 204 in its righthand position shown in Figure 5, butif sulicient axial shifting force is applied to the shaft 204, theresulting camming action of the interengaged shoulders 250 and 252 willrock the arm and release the shoulders and thus permit the spring 248 toshift the shaft 204 to the left to consequently disengage the gears 20Sand 132 and shift the countershaft 122 from itshand feed to automaticfeed position.

`In order to operate the aforedescribed preset feed mechanism. the knob210 is pushed inwardly to rock the arm its; until the shoulders 250 and252 are disengaged to permit the shaft 204 to shift to the left anddisengage the gears 2% and 132. Thereupon the knob can be rotated tomove the nut 226 axially along the shaft 204 and set the counter 214 forany desired distance of travel, up to a maximum of approximately l0inches, which has been designed into the machine illustrated. When theshaft 284 is in its right-hand position and the automatic feed nut 226abuts against the top cap 44, i. e., against the inner end of thebearing 206, the counter 214 is set to zero. lt thus will be seen thatas the shaft 204 is rotated to set the preset feed mechanism, theautomatic feed nut 226 travels to the left along the shaft until theright-hand end of the nut is a predetermined distance from the top cap44 of the gear housing 46. At the same time, this distance is registeredon the counter 214 in terms of inches and tenths of an inch ofpredetermined l travel of the boring bar 74. For example, when the nut226 nearly abuts the collar 234, the counter may register 9.8 inches, asshown in Figure 5. Thereupon, the knob 21E) is pulled out to shift theshaft 204 to the right, against the action of the spring 248, to therebyengage the gears 203 and 132 and disengage the stop lugs 244 and 246.The shaft 204 is then held inthis position by the re-engagement of thedetent shoulders 250 and 252.

When the machine is then operated in automatic feed, it will be seenthat the shaft 204 will rotate in the opposite direction from its manualsetting direction, so that the nut 226 will travel along to the rightuntil it engages the top cap 44 of the gear housing 46, whereupon areaction thrust will be exerted on the automatic feed tube 228 whichcauses disengagement of the aforementioned detent shoulders 250 and 252and permits the spring 248 to move the shaft 2th! to the left, thusdisengaging the gears 208 and 132 and causing the countershaft 122 toshift from automatic to hand feed position.

in connection with the foregoing preset feed mechanism, it will be seenthat unless the pitch of the threads on the shaft 204 is impracticallysmall, such threads would have to be of undue length unless the shafthas a reduction drive from the shaft 174. `The gears 212 and 134 providesuch reduction. It also will be seen that as the shaft 204 is rotated bythe reduction drive, the rotatable counter $.14 will return to a zeroindication during travel Vof the boring bar 74 through its preset feeddistance.

It also will be noted that the machine cannot be operated in automaticdrive unless a preset feed distance is set into the preset feedmechanism.

The machine also embodies mechanism for positively preventing overtravelin the event that the boring bar 74 has advanced to nearly its maximumextended position and the automatic feed mechanism is inadvertentlypreset to advance the boring bar beyond such maximum extended position.Unless such overtravel preventing mechanism is provided, the downwardlyfacing shoulder 78 at the upper end of the boring bar 74 would engagethe bottom wall of the lower gear housing 34 and thus possibly damagethe machine considerably when it is power driven.

The overtravel preventing mechanism also involves the rocker arm 140which is provided with another aperture having a bushing 258eccentrically receiving the feed screw extension M2 when the arm 140- isin the position wherein the detent shoulders 250 and 252 are engaged.The edges of the bushing 258 are beveled for cammingengagement to centerthe bushing with respect to the extension 102 9 and thereby rock the arm140, by a correspondingly beveled washer 260 carried by a pin 262(Figure 3) extending through a diametric slot `264 in the feed screwextension 102.- A rod 266 is secured to the pin 262 and extends throughthe screw 100 to a point opposite diametric slots 268 (Figure 20) in andadjacent the lower end of the screw. At and beyond the slots 268, thefeed screw 100 is reduced and provided with a smooth, unthreaded portionslidably mounting a collar 270 engageable by the ring 90, which isengaged with the feed nut 92, just before the shoulder on the bar '74,at its limit of advance, engages the lower wall of the housing 34. Thecollar 270 is fixed to the rod 266 by a transverse pin 272 extendingthrough the slots 268 in the feed screw 100. A spring 274 interposedbetween the collar 270 and a second vcollar 276 fixed on the lower endofthe feed screw 100 by a pin 278 urges the rod 266 into an upwardposition to relieve any camming action between the Washer 260 and thearm 140 or bushing 258. Engagement of the ring 9i) with the collar 270pulls the beveled washer 260 into the bushing 258 to effect a cammingaction between their beveled surfaces that causes the arm 140 to rock ina direction tok disengage the detent shoulders 259 and 252 on the arm140 and on the automatic feed tube 22S. Consequently, the latter will beshifted by the spring 248 to a hand feed position.

As pointed out heretofore, when a positively-engageable clutch mechanismis disengaged under load, the result is to damage such mechanism.Moreover, disengagement of such a mechanism under load usually requiresan extremely large force. For example, it is estimated that when themachine illustrated is of a size to make a 6 inch diameter cut and ismaking such a cut in automatic feed, the load on the dive key 152 is 750pounds, and that part of vthe key engaged with the gear 136 is under apressure of 5,000 pounds per square inch when fully engaged. Suchpressure increases substantially to infinity as the key 152 is cammedout of the groove 154. Consequently, if the dive key 152 is disengagedwhen theV power train constituting the automatic drive for the' feedmechanism is under load, not only would metal be shaved from the keyand/or from the sidewalls of the groove 154 in the gear 136, but also itwould require a considerable force to shift the countershaft 122 fromits hand feed to automatic feed position. y

This invention overcomes the aforedescribed disadvantages by providingmeans to relieve the load on the power train on shifting of thecountershaft 122 from its hand feed to its automatic feed position. Thisfeature is particularly advantageous in the; instant machine wherein thepreset feed mechanism automatically disengages the automatic drive forthe feed mechanism when such drive is under load.

The load-relieving function is accomplished by securing the gear 144 tothe countershaft 122 by a special key 280 engaging a special keyway 282in the countershaft 122, shown best in Figures 14 to 17. The keyway 282and that portion 2%4 of the key 280 engaged therein are formedv assections of a helix Ahaving a direction and angle such that when thecountershaft 122 is shifted from its hand feed (Figure 14) to itsautomatic feed position (Figure 15), the gear 144 is rotated relative tothe countershaft in a direction to relieve the load on the power traincomprising the automatic drive for the feed mechanism. In vother words,such axial shifting of the countershaft 122 effects a slightly backwardrotation of the gear 144 relative to its normal direction of rotationwhen the automatic drive is operative. Thus, the load on the power trainis relieved at the moment when `the dive key 152 disengages from theslot `or groove'154 in the gear 136 so that such clutch mechanism'willnot be damaged. l

It will be seen that the load can -be thus relieved substantially at thecommencement of axial shifting movement of the countershaft.Nevertheless, shifting motion of the countershaft 122 is essentialtorelieve the load, so

10 that at the commencement of such shifting motion, the load is notrelieved and it still requires a considerable force to initiate suchshifting motion. vThis disadvantage is overcome by forming the base orfoot portion of the train is relieved before the commencement ofdisengaging motion of the clutch device. Consequently, only a smallforce is needed to automatically shift the countershaft 122 from handfeed to automatic feed position.

In some instances, a cut may be completed before the boring bar travelsthrough the :distance set into the preset feed mechanism, so that thelatter will not be operated to disengage the automatiic drive for thefeed mechanism. In that event, an operator may shut off the drivingmotor, push in the knob 128 to place the machine in hand feed, andretract the bar by reverse rotation of the crank 114. Suchreverserotation of the crank 114, with the shaft 204 still in itsrighthand position, because the detent shoulders 250 and 252 are stillengaged, causes the nut 226 to travel along to the left. Should the nut226 engage the collar 234 while the gears 208 and 132 are still engaged,continued reverse rotation of the crank 114 might seriously damage thepreset feed mechanism.

rIhe aforementioned possibility of damage to the preset feed mechanismis avoided, however, by providing the lug 238 on the nut 226 with abeveled surface 251 Vopposed to the beveled shoulder 252, and sopositioning the surface 251 on the nut that the surface 251 will engagethe detent shoulder 252 immediately before the nut 226 could engage thecollar 234. Such engagement of the surface 251 with the shoulder 252cams the rocker arm to release the detent shoulders 25) and 252 so thatthe spring 248 will shift the shaft 204 to the left and disengage thegears 268 and 132. Consequently the boring bar can be fully retracted bythe crank 114 without damage to the preset feed mechanism.

It thus will be seen that the objects of this invention have been fullyand effectively accomplished. It will be realized, however, that theforegoing specific embodiment has been shown and described only for thepurpose of illustrating the principles of this invention and is subjectto extensive change without departure from such principles. Therefore,this invention includes all modilications encompassed within the spiritand scope of the following claims.

I claim:

l. In a machine having a translatable and rotatable part and a pair ofinterengaged, relatively rotatable elements, one rotatable with thepart, for effecting translation of the part on relative rotation betweenthe elements, the combination of:` differential gearing meanshaving tworelatively rotatable members and a third member which rotates at thedifferential rate of rotation between said two members; means fordriving one of said twomembers with one of the elements and for drivingthe other of said two members with the other of the elements; androtatable counter means driven by said third member for measuring theextent of translation of the part.

2. In aV drilling machine having an axially and rotatably movable boringbar and feed mechanism to advance or retract vthe Abar including-interengaged feed nut and feed screw elements, one rotatable with thebar, the combination of: differential gearing means having tworelatively rotatable members'and a third member which rotates at thedierential rate of rotation between said two members', means for drivingone of said two members with one of the feed mechanism elements and fordriving the other member with the other element; and rotatable counter l1 means driven by said third member for measuring the extent of axialmovement of the bar.

3. In a drilling machine having an axially and rotatably movable boringbar, feed mechanism therefor rincluding interengaged feed nut and feedscrew elements, one rotatable with the bar, an automatic drive for thefeed mechanism to advance the bar at a certain rate, shiftable means forrendering the automatic drive operative or inoperative,

and a manually-operable drive for the feed mechanism to advance orretract the bar at a different rate when the automatic drive isinoperative, the combination of: differential gearing means having tworelatively rotatable members and a third member which rotates at thedifferential rate of rotation between said two members; means fordriving one of said two members with one of the feed mechanism elementsand for driving the other member with the other element; and rotatablecounter means driven by said third member for measuring the extent ofaxial movement of the bar.

4. A drilling machine comprising: a support, a boring bar mountedtherein for axial and rotary movement; a drive for rotating said bar;feed mechanism for said bar including a feed nut element and a feedscrew element engaged therewith, one carried by said bar and the otherby said support; means operable by the drive for the bar forautomatically driving said feed elements relative to each other to movesaid bar axially at a rate proportional to its rate of rotation; clutchmeans in said automatic driving means; manually-operable means fordriving one of said feed elements relative to the other to move said baraxially when said clutch means is disengaged; differential gearing meanshaving two relatively rotatable members and a third member which rotatesat the diifercntial rate of rotation between said members; means fordriving one of said two members with one of said feed elements and fordriving the other member with the other element; and rotatable countermeans driven by said third member for constantly indicating the extentof axial displacement of said bar from a reference position.

5. in a machine having a translatable and rotatable part, feed mechanismtherefor, and a disconnectable automatic drive for the feed mechanismoperable on rctation of the part to effect translation thereof, thecombination of settable mechanism operable with the drive andindependent of translation resistance encountered by the part forautomatically disconnecting the drive on a predetermined extent oftranslation of the part.

6. The structure defined in claim 5 including rotatable counter meansoperable by the settable mechanism for indicating the predeterminedextent set by the settable mechanism.

7. The structure defined in claim 6 including means for driving thecounter means with the automatic drive, after the settable mechanism isset, to return the counter means to a zero indication during translationof the part through the predetermined extent.

8. ln a drilling machine having an axially and rotatably movable boringbar, feed mechanism therefor, an automatic drive for the feed mechanismoperable on rotation of the bar to effect advance thereof, and shiftablemeans for rendering the automatic drive operative or inoperative, thecombination of settable mechanism operable with the drive andindependent of feed resistance encountered by the bar for automaticallyshifting the shiftable means to render the automatic drive inoperativeon a predetermined extent of advance ofthe bar.

9. A drilling machine comprising: a support; a boring bar mountedtherein for axial and rotary movement; a drive for rotating said bar;feed mechanism operable by said drive for automatically .advancing saidbar; clutch means in said mechanism; settable mechanism for disengagingsaid clutch means after a predetermined ad- Vance of said bar, includingrelatively rotatable, interengaged screw and nut elements;and-'disconnectablemeans for driving one of` said' elements relative tothe other with said feed mechanism.

l0. The structure deined in claim 9 including rotatable counter meansdriven by the one element for indicating the predetermined advance setby the settable mechanism.

11. In a power train including a shaft member, a

gear member mounted thereon, and positively-engage-` able clutch meansdisengageable on relative axial movement between the members, thecombination of means separate from the clutch means interconnecting theshaft and gear members for transmission of power from one to the otherand responsive to the relative axial move- Vable clutch meansdisengageable on said relative axial movement; and key meansinterconnecting said members for transmission of power from oneto theother, said key means having a helical portion slidable in acomplementary helical keyway in one of said members and esponsive tosaid relative axial movement to disengage said clutch means foreffecting relative rotation between said members in a direction torelieve a load on the train.

14. In a power train the combination comprising: a shaft member; a pairof spaced gear members mounted thereon for relative axial movementbetween said gear members and shaft member; a dive key connected to saidshaft member and engageable and disengageable with one of said gearmembers by'said relative axial movement; and key means interconnectingthe other of said gear members and said shaft member for transmission ofpower from one to the other, said key means having a helical portionslidable in a complementary keyway in one of said members and responsiveto said relative axial movement to disengage said dive key foreffectingV relative rotation between said other gear and shaft membersin a direction to relieve a load on the train. l

15. The structure defined in claim 14 including a lost motion connectionbetween the dive key and the shaft member for delaying disengagingmovement of the former until the load has been relieved.

16. In `a drilling machine having an axially and rotatably movableboring bar, feed mechanism therefor, an automatic drive for the feedmechanism operable on rotation of the bar to effect advance thereof andincluding a shaft member and a gear member mounted thereon for relativeAaxial movement therebetween and for transmissionof power from one tothe other, and positively-engageable clutch means for rendering thedrive operative or inoperative and engageable and disengageable byrelative axial movement between the shaft and gear members, thecombination of: ettable mechanism operable with the automatic drive forautomatically effecting relative axial movement between the shaft andgear members in a direction to disengage the clutch means on apredetermined extent of advance of the bar; and helical key meansinterconnecting the shaft and gear mem s and effective on saiddisengaging relative axial movement to ycause relative rotary movementbetween the members in a direction to relieve a load on the automaticdrive.

17. A drilling machine comprising: a support; a boring bar mountedtherein for axial and rotary movement; a drive for rotating said bar-gfeed mechanism operable by said drive for automatically advancing saidbar; including a shaft member and a gear member mounted thereon forrelative axial movement therebetween and for transmission of power fromone to the other; positively-engageable clutch means in said feedmechanism and engageable and disengageable by said relative axialmovement; settable mechanism for automatically effecting relative axialmovement between said members to disengage said clutch means on apredetermined advance of said bar, including interengaged screw and nutelements and disconnectable means for driving one of said elements withsaid feed mechanism; and key means interconnecting said shaft and gearmembers for transmission of power from one to the other, said key meanshaving a helical portion slidable in a complementary keyway in one ofsaid members and effective on said clutch-disengaging relative axialmovement to impart relative rotation between said members in a directionto relieve a load on said feed mechanism.

18. In a drilling machine having an laxially and rotatably movableboring bar, feed mechanism therefor including interengaged feed nut andfeed screw elements, one rotatable with the bar, an automatic drive forthe feed mechanism to advance the bar `at a certain rate, shiftablemeans for rendering the automatic drive operative or inoperative, and amanually-operable drive for the feedmechanism to advance or retract thebar at a different rate when the automatic drive is inoperative, thecombination of: differential gearing means having two relativelyrotatable members and a third member which rotates at the differentialrate of rotation between said two members; means for driving one of saidtwo members with one of the feed mechanism elements and for driving theother member with the other element; first rotatable Vcounter meansdriven by said third member for constantly indicating the extent ofadvance of the bar from a completely retracted position; settablemechanism operable by said third member for automatically shifting theshiftable means to render the automatic drive inoperative on apredetermined extent of advance of the bar from any given position; andsecond rotatable counter means operable with said settable mechanism forindicating the predetermined extent of advance set by said settablemechanism.

19. The structure defined in claim 18 including a driving connectionbetween the settable mechanism and the second counter means forreturning the latter to a zero indication during the predeterminedextent of advance of the bar.

20. The structure defined in claim 18 including abutment means movingaxially with the bar and means connected to the settable mechanism andengageable by said abutment means for operating the shiftable means torender the automatic drive inoperative at the limit of advance of thebar.

21. In a drilling machine having an axially and rotatably movable boringbar, feed mechanism therefor, an automatic drive for the feed mechanismincluding an axially-shiftable shaft offset from the bar, and clutchmechanism in the automatic drive and operable by shifting the shaft, thecombination comprising: a shaft-shifting assembly including a partrotatable with the shaft and effective on arresting of rotation of saidpart to shift the shaft and disengage the clutch mechanism; and settablemechanism for automatically effecting said arrestment on a predeterminedextent of advance of the bar from any given position including anaxially-shiftable assembly comprising interengaged screw and nutelements, one xed against rotation, disconnectable means for rotatingthe other of said elements with the automatic drive to effect axialmovement of said one element, said means being disconnectable byshifting said assembly, manually operable means for rotating said otherelement to adjust the axial position of said one element ondisconnection of said disconnectable means, detent means restrainingshifting of said assembly in a direction to disconnect saiddisconnectable means, spring means urging said elements to shift in saiddirection, xed abutment means engageable by said one element to shiftsaid assembly in said direction and means shiftable with said assemblyfor arresting rotation of said part.

22. The structure defined in claim 21 including a rotatable counterdriven with the other element for indicating the predetermined extent ofadvance set in the mechanism.

23. The structure defined in claim 21 in which the feed mechanismincludes interengaged feed nut and feed screw members, one rotatablewith the bar and including differential gearing means having tworelatively rotatable parts and a third part which rotates at thedierential rate of rotation between said two parts, means for drivingone of said two parts with one of the members and the other part withthe other member, another rotatable counter driven by said third partfor constantly indicating the extent of axial displacement of the barfrom a retracted position, and means for driving the disconnectablemeans by said third part.

24. The structure defined in claim 21 including abutment means movablewith the bar and means engageable by said abutment means fat the limitof advance of the bar for releasing the detent means.

25. The structure dened in claim 24 in which the detent means includes aspring-biased rockable member and interengaged beveled shoulders on saidrockable member and the other element, and the detent releasing meansincludes cam means for rocking said rockable member to disengage saidshoulders.

26. In a machine having a translatable and rotatable element and anon-translatable element engaged therewith and rotatable relativethereto for effecting translation thereof, the combination of indicatormeans for showing the extent of translation of the translatable elementcomprising: differential means having two relatively rotatable membersand a third member which moves at a rate proportional to thedifferential rate of rotation between said two members; means fordriving one of said two members with one of the elements and for drivingthe other of said two members with the other of the elements; andindicia means associated with said third member for measuring the extentof translation of the translatable element.

References Cited in the file of this patent UNITED STATES PATENTS

